1. Field of the Invention
The present invention relates to a magnetic sensor and a magnetic head.
2. Related Background Art
Various devices for detecting external magnetic fields have conventionally been known (see, for example, the following Patent Literature 1). Magnetic heads and magnetic sensors used in HDD and the like, for example, have been desired to detect magnetic fields from minute areas and exhibit high output characteristics. Conventional TMR devices have a spin-valve structure and exhibit relatively high output characteristics. The devices have been made finer in order to detect magnetic fields from minute areas. However, making the devices finer increases their resistance. For example, a limit begins to appear in areas with a recording density of 1 Tbit/inch or higher, thereby necessitating other structures and systems.    Patent Literature 1: Japanese Patent Application Laid-Open No. 2007-299467.